PLATE XXI 



FIG. I. Parancmertcs californica Coe. Dorsal view of anterior portion of 

 body, showing position of the two small ocelli on tip of snout. Position of 

 cephalic furrows indicated by dotted lines ; br, brain ; In, lateral nerve. X 12> 



FIG. 2. P. californica. Dorsal view of tip of snout, shosving the two frag- 

 mented ocelli. X I2 - 



FIG. 3. P. californica. Stylet apparatus of proboscis, showing central stylet 

 and basis and four pouches of accessory stylets. X45- 



FIGS. 4-8. P. californica. Central stylets and bases from five individuals, 

 showing variations in size and shape. X 9- 



FIG. 9. P. californica. Accessory stylets more highly magnified, showing 

 the peculiarly striated basal portion of each. The central stylets in figs. 4-8 

 are perfectly similar to these. X 22O 



FIGS. 10-12. Tctrastcmma signifcr Coe. Central stylets and bases from three 

 individuals. X 2 -- 



FIGS. 13-14- T. bilincatum Coe. Outlines of bases of central stylets. X 380. 



FIG. 15. T. nigrifrons Coe. Stylet apparatus of proboscis. X f>- 



FIGS. 16-17. T. nigrifrons Coe. Central stylets and bases, showing more 

 opaque posterior portions. X I 8- 



FIGS. 18-19. T. nigrifrons. Outlines of accessory stylets. X 220. 



FIGS. 20-23. ^- nigrifrons. Outlines of central stylets and bases, showing 

 variation in form and size. Figs. 2022 from very small individuals ; fig. 23 

 from the largest specimen collected. X 22 - 



(2lS) 



